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JEE Main 2026 · 6 Apr · Shift 1, Physics question 46

Refer to the circuit diagram given below. The heat generated across the 6 Ω resistance in 100 second is α100\dfrac\alpha{100} J. The value of α\alpha is ________. (Nearest integer)

A 2 V cell and a 3 Ω resistor in series feed two parallel branches: the upper has 6 Ω in series with a 3 V cell, the lower has 4 Ω.
Answer and worked solution

Official answer: 3477

Polarity (as drawn). Call the junction after the 3 Ω resistor X and the right-hand wire Y, and let V=VX−VYV=V_X-V_Y.

  • Main branch: VX=VY+2−3IV_X=V_Y+2-3I.
  • 6 Ω branch: (V−3)/6(V-3)/6 from X to Y.
  • 4 Ω branch: V/4V/4.

KCL.
V−36+V4=2−V3 ⇒ 9V=14,V=149.\frac{V-3}6+\frac V4=\frac{2-V}3\ \Rightarrow\ 9V=14,\qquad V=\frac{14}9.

Current in 6 Ω.
∣14/9−36∣=1354 A.\left|\frac{14/9-3}6\right|=\frac{13}{54}\text{ A}.

Heat in 100 s.
(1354)2(6)(100)=34.77 J=3477100 J.\left(\frac{13}{54}\right)^2(6)(100)=34.77\text{ J}=\frac{3477}{100}\text{ J}.

Answer: 3477